81005955 has 32 divisors (see below), whose sum is σ = 134120448. Its totient is φ = 41721600.

The previous prime is 81005933. The next prime is 81005963. The reversal of 81005955 is 55950018.

It is not a de Polignac number, because 81005955 - 2⁸ = 81005699 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 65190 + ... + 66420.

It is an arithmetic number, because the mean of its divisors is an integer number (4191264).

Almost surely, 2^81005955 is an apocalyptic number.

81005955 is a deficient number, since it is larger than the sum of its proper divisors (53114493).

81005955 is a wasteful number, since it uses less digits than its factorization.

81005955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1387.

The product of its (nonzero) digits is 9000, while the sum is 33.

The square root of 81005955 is about 9000.3308272530. The cubic root of 81005955 is about 432.6854740376.

The spelling of 81005955 in words is "eighty-one million, five thousand, nine hundred fifty-five".